The invention relates to a lens
refractive index and thickness measuring method and a device based on the differential
confocal technology, which belong to the technical field of optical precise measurement. The invention is used for the high-precision measurement of the
refractive index and the thickness of a spherical lens. The invention is based on a
ray tracing principle, utilizes an
absolute zero point of a
laser differential
confocal responding curve for accurately determining the intersection point of the front surface of the lens to be measured and an
optical axis, the intersection point of the back surface of the lens to be measured and the
optical axis, and the position of a measuring lens with or without the lens to be measured, then, the position of the measuring lens and the curvature
radius, the
focal length and the
pupil of the measuring lens which are measured in advance are utilized for carrying out
facet ray tracing calculation on two spherical surfaces of the lens to be measured and the reference reflecting surface, and finally, the high-precision
nondestructive measurement on the
refractive index and the thickness of the lens to be measured is realized. The invention has the obvious advantages of simple operation, high measuring precision, strong environmental disturbance resistance capability and the like, and can be widely applied to the refractive index and thickness measurement of various spherical lenses, particularly the refractive index and thickness measurement field of thin lenses.